


What friends do

by inasiriusrelationship



Category: Shadowhunters (TV), The Shadowhunter Chronicles - All Media Types
Genre: (and so is she), Aline pops up to shed some light on the situation, F/M, Idris - Freeform, Idris setting, Isabelle is a great big sister, Max is like 14 in this let's just pretend this ceremony is a thing the nephilim do okay, Simon is smitten, Sizzy - Freeform, Sizzy in Idris!, and assuming everything goes fine and dandy, because they are both dummies, malec are mentioned only pretty much, pshh that can totally happen, set far far away from the current show canon, sizzy get together
Language: English
Status: Completed
Published: 2017-12-27
Updated: 2017-12-27
Packaged: 2019-02-22 13:34:19
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,014
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13167987
Author URL: https://archiveofourown.org/users/inasiriusrelationship/pseuds/inasiriusrelationship
Summary: Max's mission clearance ceremony is coming up and she's the only one going anyway, and Simon is filling in for Raphael at some Downworld representatives meeting, so why not offer him a room? That's what friends do, right?





	What friends do

**Author's Note:**

  * For [Paradise145](https://archiveofourown.org/users/Paradise145/gifts).



> Okay, so this was written as a gift for the Shadowhunters Betas Winter Fic Exchange 2017, and it was honestly a lot of fun because I hadn't written Sizzy in a long time! College life has been kicking my butt, so this might not be the best, but I hope you enjoy, Paradise145! Hope you're having a great holiday season and enter 2018 just right :)

~~~~

“And I’m really gonna be able to go on actual field missions when I come back from this?”

Isabelle held back her chuckle as she stared down at her little brother’s eager face. “Well, you’ll be cleared to, but that doesn’t mean older, more experienced Shadowhunters won’t be prioritized.”

“Yeah, but I’ll be  _ able _ to go, right?” he insisted, eying her up and down suspiciously. “You won’t try to interfere with that, will you?” Isabelle rolled her eyes, even though something in her chest clenched at the thought of Max actually going out on real missions. “Let’s just say you might be stuck with me as a partner for a couple years.” The young Shadowhunter began to pout and she chuckled, patting him on the back. “Go pack your bags, we leave at 8.”

That was enough to get a smile back on his face and send him on his merry way. Isabelle stared after him fondly for a second before shaking herself awake and heading down to the ops center; she still had a few things to wrap up before they left, and they weren’t gonna take care of themselves.

“Izzy!”

She turned around at the sound of her name, a smile already on her lips as she pushed her chair away from her desk. “Hey Simon, what’s up?”

She could feel the vampire’s easy-going grin even as he leaned down to press a kiss to the top of her head. “Oh, not much; just stopped by to say goodbye to Clary before I go away.”

Isabelle frowned. “Away? Where are you going?”

Simon’s default setting was blabbering, and today it seemed to be on full blast. “Oh, I don’t mean away-away, and it’s not for long anyway, I just, you know, Raphael asked and I really couldn’t say no, it’s his sister’s birthday and you know how cute he is when it comes to Rosa, I just really didn’t have the heart to say no, plus it’s supposed to be really pretty there, isn’t it?” He came to a halt with his hands on his hips expectantly, and Isabelle realized she was supposed to actually answer him; chuckling, she raised both eyebrows. “Simon, I still have no idea where you’re going; slow down a bit.”

Blinking somewhat surprisedly, the vampire let out a self-depreciating chuckle as he rubbed the back of his neck. “Right, sorry. I’m going to Idris to fill in for Raphael on some sort of Downworld meeting. He says all I really have to do is be there, so I’m taking his word for it.”

Isabelle laughed. “Well, I’m sure you’ll do great. I’m actually going to Idris as well; Max has his mission clearance ceremony and we need to be a couple days early, so we’re leaving tonight.” She tilted her head. “When’s your thing?”

“Uh, 2 days from now? I think so, yeah, two days.”

The Shadowhunter tapped his shoulder playfully. “Well, you should come with us! I’m gonna have loads of free time when Max is stuck in evaluations and I can show you around. Magnus is making us a portal tonight.”

Simon beamed at her. “Really? I mean, I don’t have anything ready, I don’t even know where I’m gonna stay yet.”

Izzy waved him off. “Oh, you can have one of the rooms in the Lightwood house, it’s just me and Max anyway.” Poking his side, she smiled warmly at her friend. “It’ll be great.”

* * *

 

Isabelle hugged her brother goodbye, then pressed a kiss to Magnus’ cheek. “Take care of him, will you?”

Alec scoffed, blushing slightly, but there was a tiny smile on his face from the way Magnus simply laughed and nodded, taking his hand. “Always.” Isabelle smiled then turned around to face her two traveling companions, who seemed to be deep in a discussion about something that required Simon to move what appeared to be an imaginary sword and make whooshing noises; Max looked stuck between aww and confusion, but Simon’s delight was clear on his face. Clearing her throat, she raised a brow. “All ready?” Both boys turned towards her and smiled sheepishly, Simon rubbing at the back of his neck. “Yes, Ma’am.”

Rolling her eyes playfully, Isabelle grabbed her bag and then Max’s hand, walking through the portal with one last wave to Magnus and Alec, Simon right behind them.

They’d given Magnus explicit permission to enter the Lightwood Manor years ago (Alec was called back for Institute Head Meetings sometimes and he hated parting from his boyfriend too long), so he’d portalled them right into the foyer. Isabelle dropped her suitcase on the floor with a sigh; she’d had a long day and it was finally catching up to her.

“Max, why don’t you go up to your room and unpack? You have a big day tomorrow.” The young Shadowhunter started to pout for a second before she cast a warning glance at him and he nodded petulantly, climbing up the stairs and banging his suitcase on every step. Rolling her eyes fondly, she dropped down on the couch before noticing that Simon was still looking around, awestruck. She chuckled, and it was only slightly bitter. “Yeah, we might not be the Herondales, but we’re still big shots in Idris.  _ Mi casa es su casa _ .” When he turned to her, she pointed in the direction of the stairs with her thumb. “The guest bedroom is the first on the left. You can go and get comfortable. That bed is amazing by the way, super damn fluffy.” Okay, this time there was definitely some bitterness in her tone. “Gotta make a good impression for any important people that need to stay the night, you know?”

Simon frowned slightly, his gaze shifting from the stairs to her. “Aren’t you coming?”

Isabelle smirked mischievously. “To your bed? My, my, Mr. Lewis, such an improper invitation. What would the servants say?”

The Daylighter blushed heavily. “I-I didn’t mean - like - you, we - not - you have servants?” He finally exclaimed, looking around as if expecting them to just pop out. Isabelle laughed openly, dropping her head back on the couch. “Relax, Simon. It was a joke; just us and Max for the next two days.” She closed her eyes, humming contentedly. “I’m just gonna stay here and see if I can find the will to move again without needing an energy rune.”

She missed the way Simon swallowed slightly, shifting his gaze away from her as he started up the steps. “Yep; just us. Great.”

* * *

 

When Izzy woke up again the first few rays of sun were slipping through the window. She had no idea how she’d let herself slip this far; she’d only intended to rest for a few minutes and then go upstairs and unpack her things – and now she didn’t even know what time it was. She blinked herself properly awake, intending to check the time on the big, heavy-looking clock that hung above the fireplace when she realized she wasn’t in the sitting room at all. 

Suddenly standing up straight, she realized she was lying on top of her bed, wearing the same clothes she’d had on the previous day, except her boots were off and her hair was no longer in the functional ponytail she’d wore for the afternoon of paperwork she’d had to endure. She’d been tucked under the covers, but she didn’t even remember climbing up the stairs. Frowning in confusion, she glanced at her bedside table, the one Alec had split his eyebrow on years ago (it truly wasn’t Isabelle’s fault), and found a note written in what appeared to be a sheet of music; Isabelle snorted to herself. Only Simon would bring a music notebook to Idris.

 

_ Iz, _

_ You were pretty out of it yesterday. I’m assuming you had a busy day planning the trip; sorry I wasn’t much help. I went back downstairs to get some water and figured you’d prefer sleeping in your bed and not the couch (however fancy it might be). _

_ P.S. – Please don’t kill me I was just trying to be a good friend _

_ Simon _

 

She traced the nickname at the beginning with a slight smile. Simon really was a nice guy; she had zero clue how he managed to get her up the stairs without waking her up, though. Sighing, the Shadowhunter threw her legs over the side of the bed, heading for the kitchen to get an early breakfast, since she knew there was no way she’d ever get back to sleep now.

Her socked feet padded softly on the wooden floors, and Izzy found herself humming quietly; it had been a long time since she’d come to this house, and even if she hadn’t had what she’d learned from Simon and Clary to be a “normal” childhood, she still had some fine memories attached to it. She wove her way around the furniture in the dark with ease, opening the fridge once she’d reached the kitchen. She’d asked Aline to stock it up for her earlier in the week since she’d knew they wouldn’t be getting in until late -which reminded her, they were supposed to meet up for coffee in the afternoon. She hoped her friend wouldn’t mind her taking Simon along. Grabbing the milk carton and some eggs, she turned around in the direction of the pantry to get some flour – she’d been craving pancakes. She pushed the door open with her hip, only for it to bounce back at her. “Ouch!”

“Simon?” She peeked inside to find the vampire with a hand to his side, grimacing slightly. “Shit, sorry!” He chuckled, waving her off. “It’s fine, don’t worry about it. I was just looking for some crackers.” Izzy searched the shelves for a couple of seconds before nodding. “Yeah, I see them, hold on.” She squeezed into the room, making for the package before she realized how high up they actually were, and how barefoot she was at the moment – this was why she had the seven-inch rule. She heard Simon snicker slightly behind her, and turned around to glare at him, arms crossed over her chest. The Daylighter held his hands up in surrender. “Sorry, Iz, it’s just funny.”

She rolled her eyes and huffed, flipping back around and stretching on her toes to try and reach the package. “I don’t see what’s funny about it.” The vampire chuckled as he took a step forward, reaching over her to grab the crackers. “Well, you’re a real badass and I don’t think I’ve ever seen you without heels on, so I’ve never actually realized how adorably short you are.” She felt his breath on her ear as he said it, the distance between them almost nonexistent, and it somehow made her shiver. Which was stupid, because this was Simon, and  _ damn when had he started smelling this good? _

She cleared her throat and turned around, nudging him playfully to try and shake her mind off it. “I also need some flour, since you’re in such a gentleman mood this morning.” She suddenly remembered how she’d woken up, and ducked her head to avoid his gaze as she got her next words out quickly. “Oh, and uh, thanks for getting me to bed last night.” Simon blinked at her, seemingly a little dazed – she attributed it to the early hour – before nodding. “Yeah, sure, no problem.”

She smiled. “Great. Pass me the flour, then?”. The vampire’s gaze shifted to the ingredients in her arms before he narrowed his eyes at her. “Yeahhh, I’m making the pancakes.”

Isabelle pouted, but she ended up going along with it after she burned the third one and woke Max up with the smell.

* * *

 

“And then the dude legit just turned around and walked away, I swear. Craziest thing that’s ever happened to me.” Isabelle snorted as Aline shook with laughter beside her, hand in front of her mouth as Simon finished his story about the motorcycle that had run him over. “I mean, he could’ve killed me.”

Isabelle rolled her eyes amusedly. “Simon, you’re already dead.” The vampire spluttered indignantly. “And that’s the only reason he didn’t!” Isabelle raised an eyebrow at him and he stuck his tongue out before getting up. “Yeah, yeah, yeah. I’m gonna go to the bathroom. I don’t know how you put up with this bully, Aline.” 

The Asian Shadowhunter grinned, nudging Isabelle playfully. “Oh, it’s not easy, but I manage.” Isabelle flipped them both off, albeit discreetly (Idris had one single coffee shop, and it wasn’t like they were exactly falling into the background, two daughters of prominent Nephilim families and a vampire).

As soon as Simon was out of sight, Aline smirked at her friend. “So…” she paused dramatically, making Isabelle frown slightly over her steaming mug, and then she was wiggling her eyebrows in that way the Lightwood knew meant trouble. “What’s a Daylighter like in bed?”

Isabelle choked. And coughed; then choked again, glaring at her friend as she laughed at her expense. “What the hell, Aline?” The other girl shrugged, still looking very much amused despite Isabelle’s outrage. “I’m assuming you’ve done it; even though he doesn’t seem like your type, you look pretty smitten. Which means he has to be  _ really good _ at-”

Isabelle cut her off with a sound between a laugh and a shriek. “Oh my god, stop! Simon and I are just friends, alright?”

Aline held her hands up in surrender before grabbing her mug. “Fine. I just don’t really get why.” She looked at her friend intently. “I was kidding, you know? The not being your type thing is actually good.”

Isabelle bit her lip to keep from replying and forced a smile when Simon came back to the table, ranting about the fancy soap.

* * *

 

“So, why is this guy-”

“Darth Vader, come on Max, we’ve been over this.” Simon glanced sideways at the young Shadowhunter as they sliced carrots on the opposite side of the counter. Isabelle held back a smile, continuing her task of chopping up some tomatoes (apparently, even she couldn’t ruin that).

“Right, him. Why is he so evil again?”

Simon’s exasperation and dismay were very clear on his face as he threw his hands up in the air. “I’ve told you, he’s got a really troubled past!”

Max shrugged nonchalantly. “I think it’s just a bit dramatic, to be honest. And the light up sticks seem really fake; if you ask me, seraph blades are a lot cooler.”

Isabelle thought Simon was going to faint. He'd clutched a hand to his chest and just kept repeating the words “light up stick” over and over again. Max took one look at him and laughed, tugging at his arm and throwing her a sideways smirk. “Come on, let’s finish the soup before Izzy tries to.”

“Hey!” She cried out offendedly, but Simon nodded solemnly at her younger brother. “We might have our differences, but I’ll always call truce on that front.” The two boys shook hands as if celebrating an overly serious treaty, and Isabelle glared before throwing a tomato at the vampire, hitting him square in the chest and staining his pristine white t-shirt. 

She swore she had no idea how it turned into her being pinned to the ground by said vampire, holding a raw turnip over her face as her little brother cheered him on to make her eat it; she had no idea how to feel about the warm sensation that spread through her when she felt his weight blanket her, or about the sudden hunger she felt when she flipped them over and ended up straddling his hips instead. The shocked look on his face said he didn’t either, so she quickly got up and scolded the two of them before announcing she was going to bed in a tone that was most definitely at least 3 octaves higher than her normal one.

Isabelle smiled proudly as the Consul deemed her brother (along with a few other Shadowhunters his age, but who cared) fit for duty. She knew she’d be worried sick every time he even went out on a routine patrol, but she also couldn’t help the surge of pride that washed over her when Max turned to face her, a huge grin splitting his face.

Simon chuckled beside her. “You look like such a proud mother hen.” She rolled her eyes and punched his shoulder playfully. “Ha-ha. We both know I’m not exactly mom material.” She felt a twinge of sadness at her own words but brushed it aside. She’d never been particularly hasty on the whole starting a family thing, like she was aware some Shadowhunters younger than her already were. Her brothers were more than enough to keep her content for now. She clapped along with the rest of the onlookers as the young Nephilim were led down the side of the small little stage that had been set up at the Gard, then started walking towards her brother to congratulate him, but Simon frowned, touching her elbow and gently drawing her to a pause.

“Is that really what you think?” At the look of pure bewilderment that she must’ve given him, he sighed and let his fingers run down her arm until they intertwined with hers, then squeezed softly. “You’d make a great mother, Isabelle.” She felt her lips part in surprise as she blinked up at him, completely at a loss for what to say to the open  _ certainty _ that she could see in his face, feel in his voice. Luckily, he seemed to pick up on her perplexity, because he quickly let go and went back to his usual lightness, giving her a playful wink as he moved past her. “Just leave the cooking to me, alright?”

The Shadowhunter had to fight really hard to wipe the dopey smile his words caused off her face; she had a big couple of hours of networking to go through before she could take her leave.

* * *

 

Isabelle lay in bed that night for a long time, facing the ceiling and telling herself that she didn’t like Simon that way. That  _ Simon _ didn’t like  _ her _ that way. They were friends. Great friends, even; it had surprised her how easy it had been for her to trust the easy-going Daylighter, but he’d been there for her when she’d needed him to, and he’d let her in when he was hurting as well. Sure, he was attractive, but Isabelle had been with plenty of attractive people before. She didn’t exactly need the ego boost, even if she had been alone for a rather long time now.

_ By the angel _ , then why was she suddenly so damn giddy around him? It had never been like this. Sure, sometimes he would give her that smile that made his eyes crinkle a bit at the corners and that seemed way too big for his face and her knees would go weak for a second; and ever since he’d let his hair grow a little longer she’d sometimes get this little tingling in her hands, like she was itching to run her fingers through the chocolate strands. And maybe when he and Maia broke up she’d been a little too happy considering both her friends had been miserable at the time, but really, she didn’t…

Isabelle sat up like a lightning bolt. Was it possible that she did, in fact, have feelings for Simon? Her heart sped up at the thought, and somehow every beat just felt like a confirmation. Shaking her head and completely taken aback by the realization, she got out of bed and grabbed her robe, lacing it up as she went down the stairs and into the kitchen for a glass of water.

She nearly jumped out of her skin when someone touched her shoulder, disheveled as she felt, and the next thing she knew it she had Simon’s arm twisted behind his back as she shoved him face first into the counter. “Jeez, Izzy, it’s me,  **_ouch_ ** , it’s me.”

Isabelle mentally cursed herself before letting him go, dropping her head in her arms as she sat on the kitchen island. “Simon, don’t jump me like that, it’s four a.m!” she grumbled out, refusing to look at him.

Simon rubbed at his arm with a pout. “The meeting just finished half an hour ago. They thought Raphael was coming so they scheduled it for night time. I told you all this yesterday.” He took in her disheveled appearance and frowned, touching her elbow. “Hey, you okay?”

She finally lifted her head up to face him, only to let out a tiny shriek and jump upright when she saw he was clad in just some low waisted pajama slacks. “Where the hell is your shirt?!”

The vampire blushed slightly, rubbing at the back of his neck self consciously. “I was gonna sleep, I didn’t think anyone would be down here so late. Why are you being so weird?”

Isabelle let out a sound somewhere between a groan and a growl, before punching him hard in the chest; he yelped, jumping back slightly, his mouth open in shock. “Izzy! Seriously, what the hell is going on with you?” When she didn’t reply, he came closer, putting both hands on her shoulders. “Is something wrong?”

Isabelle looked up at his concerned face and told herself it was fine. This was Simon, goofy, nerdy, friendly Simon; he’d never hurt her or mock her or cut ties with her because of what was most likely just a silly crush mixed with some loneliness. He gave her a soft, reassuring smile and she took a deep breath to explain everything to him, but then his thumb slipped under her robe to rub at the bare skin of her shoulder soothingly, and instead what came out was a rushed “I-think-I-might-be-falling-in-love-with-you!” 

She saw him freeze, felt his hand stop moving, and she swore she could even tell he’d stopped breathing (not that it would be a problem for him). A couple of minutes passed before her instincts got the better of her and she made for the stairs, something welling up inside her that told her maybe the word she’d spoken were far truer than the explanation she’d come up with in her head, but she didn’t make it to the first step.

Vampire speed carried Simon across the room even faster, and then he was pressing her against the white trimmed wall and kissing the living daylights out of her; and, wow, was this what it was supposed to feel like? Isabelle’s arms wound themselves around his neck and she pulled him closer, her fingers  _ finally _ sinking into that goddamn hair of his and tugging lightly, just to check, just to make sure it was real (the way he groaned into her mouth before nibbling on her lower lip told her it was very much real).

She’d never before felt more revulsion towards her need to breathe as when he pulled away, clearly for her benefit, but then he rested their foreheads together and his eyes peered into hers and  _ okay maybe this wasn’t so bad either _ .

“How have we never done this before? Seriously, that was… you are, I mean -  _ God _ , Izzy” She pulled him down to kiss him again, effectively cutting off his rambling; she pushed herself up on her tiptoes until eventually he picked her up by her thighs, pressing her to the wall and responding just as enthusiastically. When they finally parted again, he pressed a small kiss to her collarbone and whispered quietly. “I’ve been falling in love with you for a long time, Isabelle Lightwood.”

A warming sensation bloomed in her chest at his words, and she smiled brightly at him, but the moment was ruined by the brightness that suddenly enveloped them as someone turned on the light switch. They both turned to see Max at the top of the stairs, a bored expression on his face hiding a tiny smile. “ **_Finally_ ** . Now can we please go home? Jace owes me twenty bucks.”

**Author's Note:**

> As always, please leave a comment with your thoughts and opinions, and some kudos if you liked this :)


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